I've created a relationship like this example
Mailboxes: Sharing vs. Relationships :: Zimbra :: Blog

zmprov ga secondary@domain.com | grep zimbraId
zmprov ma primary@domain.com +zimbraChildAccount {zimbraIdSecondary}
zmprov ma primary@domain.com +zimbraPrefChildVisibleAccount {zimbraIdSecondary}
It works, on the webmail the 2 mailbox appears on the left into the webmail but no action are avalable.
Reply, create new mail perform 2 javascript errors.

Code:
Uncaught TypeError: Cannot read property 'identities' of null Startup1_2_all.js.zgz:28691
ZmMailApp.getIdentityCollection Startup1_2_all.js.zgz:28691
AjxCallback.run1 /:860
AjxDispatcher._postLoadCallback /:1589
AjxDispatcher.require /:1521
AjxDispatcher.run /:1503
ZmAppCtxt.getIdentityCollection Startup1_1_all.js.zgz:23629
ZmComposeController._getIdentity
ZmComposeController._setView
ZmComposeController.doAction
ZmMailApp.compose Startup1_2_all.js.zgz:28602
AjxCallback.run1 /:860
AjxDispatcher._postLoadCallback /:1589
AjxDispatcher.require /:1521
ZmMailApp.handleOp Startup1_2_all.js.zgz:28350
ZmZimbraMail._newButtonListener Startup1_2_all.js.zgz:23766
AjxEventMgr.notifyListeners Startup1_1_all.js.zgz:3617
DwtControl.notifyListeners Startup1_1_all.js.zgz:11923
DwtButton._handleClick Startup1_1_all.js.zgz:15874
DwtButton._mouseUpListener Startup1_1_all.js.zgz:16009
AjxCallback.run /:843
AjxListener.handleEvent Startup1_1_all.js.zgz:3797
AjxEventMgr.notifyListeners Startup1_1_all.js.zgz:3617
DwtControl.notifyListeners Startup1_1_all.js.zgz:11923
DwtControl.__mouseEvent Startup1_1_all.js.zgz:13040
DwtControl.__processMouseUpEvent Startup1_1_all.js.zgz:12956
DwtControl.__mouseUpHdlr
and

Code:
Uncaught TypeError: Cannot read property 'signatures' of null Startup1_2_all.js.zgz:28702
ZmMailApp.getSignatureCollection Startup1_2_all.js.zgz:28702
AjxCallback.run1 /:860
AjxDispatcher._postLoadCallback /:1589
AjxDispatcher.require /:1521
AjxDispatcher.run /:1503
ZmAppCtxt.getSignatureCollection Startup1_1_all.js.zgz:23637
ZmComposeController._initializeToolBar
ZmComposeController.initComposeView
ZmComposeController._setView
ZmComposeController.doAction
ZmMailApp.compose Startup1_2_all.js.zgz:28602
AjxCallback.run1 /:860
AjxDispatcher._postLoadCallback /:1589
AjxDispatcher.require /:1521
ZmMailApp.handleOp Startup1_2_all.js.zgz:28350
ZmZimbraMail._newButtonListener Startup1_2_all.js.zgz:23766
AjxEventMgr.notifyListeners Startup1_1_all.js.zgz:3617
DwtControl.notifyListeners Startup1_1_all.js.zgz:11923
DwtButton._handleClick Startup1_1_all.js.zgz:15874
DwtButton._mouseUpListener Startup1_1_all.js.zgz:16009
AjxCallback.run /:843
AjxListener.handleEvent Startup1_1_all.js.zgz:3797
AjxEventMgr.notifyListeners Startup1_1_all.js.zgz:3617
DwtControl.notifyListeners Startup1_1_all.js.zgz:11923
DwtControl.__mouseEvent Startup1_1_all.js.zgz:13040
DwtControl.__processMouseUpEvent Startup1_1_all.js.zgz:12956
DwtControl.__mouseUpHdlr
Same bug with IE9, Chrome and Firefox.

But it works with the old version "7.2.1 GA Release".

The use of "relationships" between mailboxes is very important for me.
Can you help me to resolve this bug.
Thank's
Olivier